SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '737ce12c422efec2526c0ca3eff101448c12b877e21f8638e0e104fbe3a3ae37' 
  AND token = 'v4AzYZMtjo7Ci3Hg+KFMgB0JVPwxvtjLsdumFaltKEA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}